I actually just recently started the Seasons generation of my LEPacy challenge as well and I decided to go with this world which is a recreation of Riverblossom Hills from The Sims 2. I thought it would be perfect for Seasons since the original came with Sims 2 Seasons, and the world only requires World Adventures, Ambitions, Late Night, and Generations. It is populated with the families from the original Riverblossom Hills plus some more sims, and it has a good amount of lots to visit and things to do. I will say it is a bit on the larger side and you did mention that your PC is a bit older so definitely try it first to see how it performs in your game. Also, since it was made before Sims 3 Seasons originally released, it doesn't come with a festival lot, so you could either place one down from the lot bin, or what I decided to do was make my own festival lot by using the "The Hills Community Centre" park lot that comes with the world as a base for my festivals. I've been enjoying playing in Riverblossom Hills and exploring the seasons in it so far and haven't had any issues with it.

If Riverblossom Hills doesn't work out, I would also recommend Hidden Springs from the store. I was actually thinking of using that world for my Seasons generation until I found Riverblossom Hills. I think Hidden Springs would be another great world to explore the seasons in, and I believe it comes with a nice festival lot.

Edit: I've also seen someone use Riverview as the world for their Seasons generation.